The present invention is related to improvements in syringes, and more particularly is referred to a novel disposable syringe.
There are thousands of different types of disposable syringes in the prior art. Most of these developments were created during the last years due to the proliferation of contagious diseases like AIDS. Handling syringes and blood for medical analysis is a potential risk of catching a mortal disease due to the growing number of people with AIDS. Therefore using disposable syringes was a useful way for decreasing the risk of contagion. Anyway, due to costs and budget shortfalls problems most hospitals were recycling disposable syringes. In order to avoid conflictive situations syringe manufacturers have developed a new type of disposable syringe including different kind of mechanisms through which the syringe can not be reused. That is, once the syringe is used for injecting a liquid, the piston can not be moved for charging the outer cylinder or tube again.
It is an object of the present invention a syringe with a novel piston which works as impelling means of drugs or diluents through a needle and at the same time as a ampoule for containing this liquid prior to be injected, as it will be explained in detail below.
Disposable syringes of the prior art basically comprises an outer tube or cylinder which may be made of plastic or glass material, narrowed at its outlet for fitting a detachable and hollow needle for injecting solutions into the body. Inside said outer cylinder or tube a piston with a rubber bulb in its end is slidable fitted comprising an elongated solid rod for drawing in a quantity of fluid. For example, this known syringe can be used for transferring a diluent from an ampoule to a flask containing a powder drug so as to form an solution to be injected to a patient. Thus, said tube-piston set works as an extracting-impelling means. This is specially useful when prior to inject a drug to a patient the nurse must mix a diluent contained in an ampoule with a powder contained in a flask. Therefore the syringe is used for transferring the diluent from the ampoule into the flask. Once the elements are mixed (powder-diluent) to the flask, the solution formed must be extracted with the same syringe for injecting it to the patient. Since these kind of ampoules usually include a rubber cap which must be bored with the needle tip during this transferring operation there is a potential risk of blunt this needle tip. If the needle tip is blunt the patient will surely feel pain and inconveniences during and after the injection.
Moreover, once diluent is injecting in to the flask containing a drug in a powder form the needle must be removed for shaking said flask for evenly mixing said diluent and powder, thus the needle must punch to a hole twice for extracting the final mixture of elements. This bothering operation takes time and in urgent and serious situations may lead to a negative and dangerous situation for the patient.
The above cited disadvantages are overcome with the syringe of the present invention. The purposed piston may contain all necessary means for immediately injecting a solution to a patient, as it may contain two different kind of elements (like a diluent and a powder drug) and in a few seconds these elements may be evenly mixed and injected as will be explained later.
It is an object of the present invention a novel syringe incorporating a new and improved piston. This syringe consist of an outer cylinder or tube for example made of plastic material (or any other suitable material without introducing unnecessary limitations to the invention), and narrowed at its outlet for fitting a detachable and hollow needle. Inside said tube or cylinder a piston with a rubber bulb in its end is slidable fitted. This piston comprises a hollow cylindrical body including one of its end a small hole defining a fluid passage between said piston and said tube. Said rubber bulb includes a longitudinal hole, defining this hole a fluid channel which may agree with the above cited hole for defining a liquid passage.
It is a further object of the present invention to provide a syringe whose hollow piston includes an outer end with a small orifice through which a liquid like a diluent may be loaded for readily carrying out a mixing operation of elements contained in the syringe as will be explained below.
It is a still further object of the invention to provide a novel syringe piston including coupling means for retaining said rubber bulb to the piston end, said retaining means capable of allowing the rotating movement of said piston in relation with said bulb.
The present invention is related with an improved and novel syringe which main novel feature resides on its piston design. The purposed syringe comprises an outer tube or cylinder made of, for example, plastic material, narrowed at its outlet for fitting a detachable hollow needle. Inside said outer tube the novel piston is slidable fitted including at its forward end coupling means defined by a coupling bolt and a retaining head which form part of the piston body. To said coupling means a rubber bulb is rotatably fitted including a longitudinal hole for allowing fluids flow from tube to the needle and from the piston to the tube. The forward end of said piston includes an orifice defining fluid communication between the inner volume of said hollow piston and the inner volume of said tube. During the operation the piston can be rotated so as to align said hole of said rubber bulb and said orifice of the piston forward end defining a fluid channel from the syringe to the hollow needle.
Summing up, the present invention is referred to a disposable syringe comprising a cylindrical tube with a forward end narrowed at its outlet including attaching means for fitting a detachable hollow needle, and this hollow cylindrical tube defines a rear opening through which a piston with a rubber bulb fitted in its end is fitted, wherein:
said piston comprises and elongated hollow body with a forward and rear end and capable of contained therein a liquid to be injected to a patient, said forward end includes a fluid communication orifice and coupling means in which said rubber bulb is rotatably fitted, said rubber bulb includes a longitudinal orifice and both coupling means and rubber bulb having restricting means capable of restricting piston rotating movement.
The term xe2x80x9cpolydosexe2x80x9d as is used herein means a predetermined volume of a drug which must be administrated to a patient in multiple doses. That is, when a predetermined volume of drug must be injected to a patient but in multiple doses due to a specific medical treatment.